1. Field of the Invention
The present invention relates to a city lifeline information collection system capable of collecting information related to lifeline services such as gas supplies, waterworks, and electricity, in particular, for rapidly collecting data (specific data) related to a state of emergency.
2. Description of the Related Art
U.S. Pat. No. 5,689,233, U.S. Pat. No. 4,888,706, U.S. Pat. No. 4,322,842, and U.S. Pat. No. 5,894,422 are related to a lifeline information collecting system, an emergency information collection, or emergency information offering system. U.S. Pat. No. 5,689,233 discloses an emergency information offering system. An object of the invention is to attain proper information collecting and offering functions by combining information infrastructures and public infrastructures upon emergencies involving lifeline facilities.
Problems caused when conventional communication equipment is used will be described below in the case where a telephone network is used.
A collection system using a telephone network is used in practice to collect general pieces of lifeline information relating to houses; for example the state of gas supplies, waterworks, and electricity, or the state in which undesirable conditions occur, however, the information collection system using the telephone line is not effective when communications are congested during a disaster. In addition, when pieces of information of 100 bytes per terminal, including information on gas supplies, waterworks, and electricity, are to be collected for 200,000 terminals or more, the number of hours required when the telephone network is used is determined by 30 secondsxc3x97200,000 terminals=1,667 hours. Therefore, a continuous monitoring system cannot be easily realized by using a telephone network.
The problems to be solved by the present invention are as follows.
1. An information collection/monitoring system for recognizing in a short time (within several minutes) the state of damage of city lifelines (waterworks, electricity, and gas supplies) caused by a large earthquake over the whole city has not been developed in Japan or other countries. The development of such a system is considered as a problem which must be quickly solved for a countermeasure against disasters.
2. The present invention develops a system which recognizes information on water meters, electricity meters, and gas meters installed in houses and collects/monitors this information over the whole city in real time, so as to solve the above problem.
3. Since this system is an information collection system used during emergencies, delay and interruption of information collection caused by congestion of communications cannot be permitted. The problem of congestion cannot be solved by using a conventional communication system, and should be solved by developing a dedicated information collection system.
4. Since a dedicated system requires its functions and performances to be regulated, it is a technical problem to develop a system appropriate to the object.
5. It has been a difficult technical problem to develop an information collection system which continuously monitors lifelines of the whole city and has a function of collecting emergency information in a short time, while at the same time collecting detailed lifeline information.
6. This technical problem is solved by a new network configuration technique, i.e., a database network, obtained by combining high-speed databases distributed in a multi-layer radio polling system. When a disaster occurs, in order to recognize the state of the disaster, it is required to recognize the states of the lifelines of all houses within several minutes. In addition, in a disaster, communications are congested by events occurring at the same time. Therefore, assurance of communications is required evenduring disasters.
7. When a disaster occurs, in order to recognize the state of the disaster, the condition of the system up to the occurrence of the disaster must be recognized, and it must be recognized that the system is operating normally.
It is a main object of the present invention to provide a new database network system which is different from a conventional communication system.
It is another object of the present invention to constitute an information collection/monitoring system for recognizing in a short time (within several minutes) the state of damage of city lifelines (waterworks, electricity, and gas supplies) caused by a large earthquake over a whole city by using the database network system.
It is still another object of the present invention to provide a database network system, according to the above objects, which can recognize a state of the lifelines immediately before the damage caused by the large earthquake.
To this end, according to one aspect of the present invention, there is provided a database network system for collecting information comprising a terminal station group constituted by a plurality of terminal stations for acquiring changing information, to accumulate the information as data, and to transmit the data in accordance with a request, a plurality of relay database stations, each arranged for the terminal station group, for accumulating pieces of information sequentially received from the terminals as specific data and other data, and for transmitting the data in accordance with a request, and a center station for sequentially receiving parts of the specific data and the other data of an arbitrary one of the relay database stations from the corresponding relay database station, for performing a receiving operation of all the data and the specific information data a plurality of times by performing the receiving operation a plurality of times, and for accumulating all the data and the specific information data as needed.
The plurality of relay database stations includes at least one upper-layer relay database station group and a plurality of lower-layer relay database station groups arranged for one of the upper-layer relay database stations, the stations of the lower-layer relay database station group collect information of the terminal station group constituted by the plurality of terminal stations, and the center station collects information from the upper-layer relay database station.
The changing information is city lifeline information of gas supplies, electricity, waterworks, and the like, and the terminal stations are living unit terminals of houses and the like.
Specific information is extracted from changing house terminal information depending on a degree of emergency, at least two types of information including the original house terminal information:are generated, and the at least two types of information are collected in the center station for a collection time which changes depending on the degree of emergency.
The database network system is continuously operated, and a main database of the center station is designed to always hold the history of the operation by accumulating specific information data and the other data for a predetermined period of time.
As a combination of the pieces of changing information, one combination of data for reading meter values included in one of lifeline data of meters, data for collecting/monitoring information related to various maintenance jobs, and information data related to security, care of elderly people, water pressures of fire hydrants, and monitors of air-conditioners can be employed.